Package for multiple light emitting diodes
Substrates and packages for LED-based light devices can significantly improve thermal performance and provide separate electrical and thermal paths through the substrate. One substrate includes multiple electrically insulating base layers. On a top one of these layers are disposed top-side electrical contacts, including light device pads to accommodate a plurality of light devices. External electrical contacts are disposed on an exterior surface of the substrate. Electrical paths connect the top-side electrical contacts to the external electrical contacts. At least portions of some of the electrical paths are disposed between the electrically insulating base layers. The electrical paths can be arranged such that different subsets of the light device pads are addressable independently of each other. A heat dissipation plate can be formed on the bottom surface of a bottom one of the base layers.
1. A lighting apparatus comprising:
a substrate having:
a plurality of electrically insulating base layers;
a plurality of external electrical contacts disposed on an exterior surface of the substrate;
a plurality of top-side pads including a plurality of light device pads and a plurality of auxiliary electrical bond pads, each light device bond pad being sized and positioned to accommodate a light device, each auxiliary electrical bond pad being sized and positioned to accommodate a wire bond; and
a plurality of electrical paths connecting at least some of the top-side pads to the external electrical contacts, wherein at least a portion of the plurality of electrical paths is disposed between the electrically insulating base layers; and
a plurality of light devices, each light device disposed on one of the light device pads, at least one of the light devices being connected via a wire bond to one of the auxiliary electrical contacts,
wherein the light devices are connected by the plurality of electrical paths in a plurality of independently addressable groups.
2. The lighting apparatus of claim 1 wherein at least one of the independently addressable groups includes at least two of the light devices.
3. The lighting apparatus of claim 1 wherein the number of auxiliary electrical bond pads is less than the number of light device bond pads.
4. The lighting apparatus of claim 1 wherein the number of auxiliary electrical bond pads is equal to the number of light device bond pads.
5. The lighting apparatus of claim 1 wherein the plurality of light devices includes a plurality of light-emitting diodes.
6. The lighting apparatus of claim 1 wherein the plurality of light devices includes at least twelve light-emitting diodes.
7. The lighting apparatus of claim 6 wherein the at least twelve light-emitting diodes are connected in two independently addressable groups.
8. The lighting apparatus of claim 1 wherein the light devices in a first one of the independently addressable groups are light devices that emit warm white light when operated and the light devices in a second one of the independently addressable groups are light devices that emit cool white light when operated.
9. The lighting apparatus of claim 1 wherein the plurality of top-side pads includes at least one pad that is sized and positioned to accommodate both a first one of the light devices and a wire bond to connect to a second one of the light devices.
10. The lighting apparatus of claim 1 further comprising a metal heat dissipation plate disposed on a bottom surface of the substrate, wherein the metal heat dissipation plate is electrically isolated from the plurality of electrical paths.
11. The lighting apparatus of claim 1 wherein an area of each of the light device pads is maximized subject to constraints of total area available for the light device pads and a minimum spacing between the light device pads to provide electrical isolation from each other.
12. The lighting apparatus of claim 1 further comprising at least one electrically insulating upper layer overlying the top one of the electrically insulating base layers, wherein each upper layer has an opening therethrough, the opening being sized and shaped such that at least a portion of each of the light device pads.
13. The lighting apparatus of claim 1 further comprising a primary lens overlying the plurality of light devices.